The present background of the invention concerns a device for postoperative fixation back into the cranium of a plug of bone removed therefrom during a surgical operation.
It is often necessary during brain surgery to remove a plug of bone from the cranium to provide the surgeon with access to the field of operation. The plug is sawed out and must be replaced in the cranium after the operation and fixed thereto. Such plugs have long been fixed back into the rest of the cranium by suturing with loops of steel wire that extend through both and then twisting together the projecting ends of the emplaced loops. The contact between the plug and the rest of the cranium is relatively unstable, however. The two halves do not fuse together very well. The scalp can also become inflamed. Another drawback to such an approach is that the wire considerably distorts the images obtained in postoperative computerized tomography and accordingly impedes definitive interpretation of the soft structures of the brain. Although using nonresorbable and physiologically compatible thread instead of wire does eliminate the last-mentioned drawback, the fixation of the plug to the rest of the skull is still unstable. The two parts can also be fixed with thin plates of compatible metal, titanium for instance (EP A 0 510 390). Such plates bridge the abutment between the parts and are screwed to both, also closing off bores introduced into the cranium prior to section. This approach, however, is also not very satisfactory. It is both complicated and time-consuming and hence not inexpensive.